1. Field of the Invention
The present invention relates to a printing apparatus and a printing method.
2. Description of the Related Art
In recent years, the performance of printers has been greatly enhanced, which tends to cause the temperature within a device to rise. As a result, it sometimes happens that discharged papers adhere to each other due to toner on the papers. In order to prevent the discharged papers from adhering, Japanese Patent Application Laid-Open No. 2001-42635 discusses a method for controlling a rotation speed of a development sleeve according to the temperature around a development apparatus. However, according to the method, a temperature sensor needs to be provided in the apparatus, which raises apparatus cost.
Under such circumstances, a technology has been developed for controlling a paper feed interval according to an applied-toner amount to prevent the discharged paper from adhering to each other. The applied-toner amount indicates an amount of toner applied on the paper. According to the technology, the applied-toner amount is detected by measuring video signals included in image data when printing. The video signals are measured to detect whether each pixel forming an image is to be exposed.
Since the number of pixels to be exposed when printing the image data, can be obtained by measuring the video signals, the amount of toner necessary for printing, that is, the applied-toner amount can be found. However, in this case, if the paper feed interval is controlled only after the applied-toner amount is obtained, the printing interval becomes too long.
Therefore, when performing a printing job for a plurality of copies, the applied-toner amount for each page is recorded when outputting the first copy. As to the second or later copy, the applied-toner amount recorded for the first copy is used to control the paper feed interval between pages. However, the above-described technology could not be used in certain inexpensive printers, since the certain inexpensive printers operating as a stand-alone apparatus could not recognize the plurality of copies.
On the other hand, an average printer includes a memory medium having a large capacity therein to store a whole image data for a plurality of pages. Accordingly, when performing the printing job for the plurality of copies, the image data of a first copy is stored in the memory medium, and the printing of a second or later copy is performed using the stored image data. Since the certain inexpensive printers do not have the memory medium having a large capacity, the inexpensive printers cannot store the whole image data for the plurality of pages.
When printing the image data for the plurality of pages, the certain inexpensive printers divide the plurality of pages into units of several pages, sequentially stores the image data for the several pages in the memory medium, performs printing, and deletes the image data. These operations are repeated by the inexpensive printers. Accordingly, in a case where the certain inexpensive printer perform the job for printing the plurality of copies, a host side such as a personal computer (PC) generates the number of image data corresponding to the number of the copies. The printers receive the image data from the host side, and print each copy.
More specifically, the certain inexpensive printers can regard the printing of the plurality of copies only as printing one copy a plurality of times. Even if there is a plurality of jobs that can be regarded as the same, those jobs are processed as the independent printing job that has no relations with each other. Therefore, when printing the plurality of copies, the printer could not control the paper feed interval by using the applied-toner amount recorded for the first copy as described above.